President Sata, who was being treated in the UK, died in London’s King Edward VII hospital.
Media said on Tuesday night that he died after “a sudden onset of heightened heart rate”.
It is not immediately clear who will succeed the president. The issue may be decided by the Zambian cabinet which meets on Wednesday morning.
“It is with a heavy heart that I announce the passing on of our beloved president,” cabinet secretary Roland Msiska said on national TV.
He said that Mr. president Sata’s wife and son were at his bedside.
“I urge all of you to remain calm, united and peaceful during this very difficult period,” Mr Msiska added.
Mr. Sata’s death comes just days after Zambia celebrated the 50th anniversary of independence from the United kingdom.
Mr Sata is the second Zambian leader to die in office after Levy Mwanawasa in 2008.
